230 THE UROGENITAL SYSTEM 



Anomalies. If the lips of the slit-like urogenital opening on the under surface of the 

 penis fail to fuse, hypospadias results. Rarely there is a similar defect on the upper sur- 

 face epispadias. 



True hermaphroditism consists in the presence of both testes and ovaries in the same 

 individual. It is of rare occurrence in birds and mammals, is not uncommon in the lower 

 vertebrates, and is the normal condition in many invertebrates (worms, molluscs). Ac- 

 cording to Pick (1914), there are only fourauthentic'cases in man; these have on one side, 

 at least, a combined ovotestis. The internal genitalia are faultily bisexual. The external 

 genitalia show mixed male and female characteristics. The secondary sexual characters 

 (beard, mammas, voice, etc.) are usually intermediate, tending now one way, now the other. 



False hermaphroditism is characterized by the presence of the genital glands of one 

 sex in an individual whose secondary sexual characters and external or internal genitalia 

 resembles those of the opposite sex. In masculine hermaphroditism an individual pos- 

 sesses testes, often undescended, but the external genitals (by retarded development) and 

 secondary characters are like those of the female. In feminine hermaphroditism ovaries 

 are present, and sometimes descended, but the other sexual characters, such as enlarged 

 clitoris or fused labise, simulate the male. The cause of hermaphroditism is unknown. 



THE UTERUS DURING MENSTRUATION AND PREGNANCY: PLACENTA AND 

 DECIDUAL MEMBRANES 



Two sets of important changes take place normally in the wall of the 

 uterus. One of these is periodic between puberty and the menopause 

 (about the forty-fifth year) and is the cause of menstruation (monthly 

 flow). These periodic changes, comparable to the oestrus cycle in lower 

 animals, may also be regarded as preparatory to the second set of changes 

 which take place if pregnancy occurs and give rise to the decidual mem- 

 branes and placenta. 



Menstruation. The periodic changes that accompany the phenome- 

 non of menstruation form a cycle which occupies twenty-eight days. 

 This period is divided into: (i).a phase of uterine congestion six or seven 

 days; (2) a phase of hemorrhage and epithelial desquamation three to 

 five days; (3) a phase of regeneration of the uterine mucosa four to six 

 days; (4) finally, an interval of rest or slight regeneration -twelve to six- 

 teen days. 



During the first phase, the uterine mucosa is thickened to two or three 

 times its resting condition, both because of vascular congestion and on 

 account of the actual increase of connective tissue cells. The uterine 

 glands become longer, and their deeper portions especially are dilated and 

 more convoluted because they are filled with secretion. Blood escapes 

 from the enlarged capillaries by diapedesis and forms subepithelial masses. 

 At the end of this stage, the uterine mucosa shows a deep spongy layer 

 and a superficial compact layer, these corresponding to similar layers in 

 the decidual membranes of pregnancy. 



During the second phase, that of menstruation proper, the superficial 

 blood vessels rupture and add to the blood escaping into the uterine cavity ; 



